1. Field of the Invention
The present invention relates to an electronic apparatus that stores attribute information of an object to be controlled and responds to queries concerning the attribute information. The invention is also concerned with a power supply control method for controlling the power supply of an object and to a recording medium in which a sequence of processing steps of responding to queries concerning the attribute information of an object is recorded. Details of certain features of the present invention are described in European Patent Application No. 0,753,811 A1 entitled in xe2x80x9cData processing method and devicexe2x80x9d and filed by the same assignee on Jul. 12, 1996 claiming a Convention Priority on JP 178625/95, filed Jul. 14, 1997, the complete disclosure of which is hereby incorporated herein by reference.
2. Description of the Related Art
The following type of network is known in which audio-visual (AV) machines, such as television receivers, video cassette recorders, and tuners, are connected and information signals, such as audio signals, video signals, and control signals, are transmitted through the network. This type of network includes a distributed cooperative network in which AV machines connected to the network are distributed and independently operated, and are also operated in cooperation with each other in response to an information signal transmitted via the network.
In the distributed cooperative network, an electronic apparatus, which serves as a node, has a service registry that manages attribute information of a service module formed of an object to be controlled. Accordingly, it is possible for each apparatus to access a service module of another electronic apparatus via this network, thereby effecting a distributed cooperative operation.
In a household AV network, it is highly likely that the connection state of AV machines is changed, it is preferable that the service registry of one node does not store information concerning the service module of another node.
The above AV network includes not only television receivers, whose connection state is normally fixed, but also portable compact disc (CD) players and video cameras, whose connection states may be changed. It is wasteful and unnecessary to store information concerning the machines, which may be disconnected at any time, in a specific server when they are connected to a network.
A proxy server, which integrally controls other servers, may be used for storing information concerning the AV machines when they are connected to the network. It is very likely, however, that even the proxy server be disconnected since the household AV machines may be frequently connected to and disconnected from the network. It is thus necessary to cope with the disconnection of the AV machines. Further, information concerning the AV machines stored in a proxy server is not always guaranteed because the connection state may be changed by the time a search has been conducted. It is therefore necessary to check the data when necessary.
On the other hand, in the distributed cooperative network in which service registries of the respective nodes are operated in cooperation with each other, it is necessary for the central processing units (CPUs) and the service modules of the respective nodes to be constantly operated to monitor and process a search request packet flowing in the network. Accordingly, a large amount of power is consumed.
In a system in which the service registries of the respective nodes in a network are operated cooperatively, a message to be delivered without specifying a destination, which is referred to as a xe2x80x9cbroadcast messagexe2x80x9d, is transmitted even if all the service modules within a node are not used. By using this broadcast message, the service registry executes processing on a search request and transmit a search result. In order to handle the broadcast message, the CPU should always be operated, thereby wasting power even when the service modules are not in use.
Accordingly, in view of the above background, it is an object of the present invention to provide an electronic apparatus that eliminates the need for the CPU of the service registry of each node to be constantly operated for responding to a broadcast message, and also to provide a method for controlling the power supply of the above type of electronic apparatus and a recording medium in which a program implementing the above power supply control method is recorded.
In order to achieve the above object, according to one aspect of the present invention, there is provided an electronic apparatus for controlling at least one object. The apparatus includes attribute information storage means for storing attribute information of at least one object. Attribute information management means manages the attribute information storage means and switches off a power supply after transmitting the attribute information stored in the attribute information storage means to attribute information management means provided for an external electronic apparatus and delegating the external electronic apparatus to respond to queries provided from an external source concerning the attribute information stored in the attribute information storage means.
According to another aspect of the present invention, there is provided an electronic apparatus for controlling at least one object. The apparatus includes attribute information storage means for storing attribute information of at least one object and for storing, upon being delegated by a first external electronic apparatus, attribute information of at least one object of the first external electronic apparatus. Attribute information management means manages the attribute information storage means and responds to queries provided from an external source concerning the attribute information of at least one object of the electronic apparatus stored in the attribute information storage means and to queries provided from the external source concerning the attribute information of at least one object of the first external electronic apparatus.
According to still another aspect of the present invention, there is provided a power supply control method for controlling a power supply of at least one object. The method includes an attribute information acquiring step of acquiring attribute information of at least one object, and an attribute information management step of managing the attribute information acquired in the attribute information acquiring step and switching off the power supply after transmitting the attribute information to an external electronic apparatus and delegating the external electronic apparatus to respond to queries concerning the attribute information provided from an external source.
According to a further aspect of the present invention, there is provided a power supply control method for controlling a power supply of at least one object. The method includes an attribute information acquiring step of acquiring attribute information of at least one object and acquiring, upon being delegated by a first external electronic apparatus, attribute information of at least one object of the first external electronic apparatus, and an attribute information management step of responding to queries concerning the attribute information of at least one object of the electronic apparatus acquired in the attribute information acquiring step and to queries provided from an external source concerning the attribute information of the first external electronic apparatus.
According to a yet further aspect of the present invention, there is provided a recording medium in which a program implementing the following process is recorded. The process includes an attribute information acquiring step of acquiring attribute information of at least one object, and an attribute information management step of switching off a power supply after transmitting the attribute information acquired in the attribute information acquiring step to an external electronic apparatus and delegating the external electronic apparatus to respond to queries concerning the attribute information provided from an external source.
According to a further aspect of the present invention, there is provided a recording medium in which a program implementing the following process is recorded. The process includes an attribute information acquiring step of acquiring attribute information of at least one object and acquiring, upon being delegated by an external electronic apparatus, attribute information of at least one object of the external electronic apparatus, and an attribute information management step of responding to queries concerning the attribute information of at least one object of the electronic apparatus acquired in the attribute information acquiring step and to queries concerning the attribute information of the external electronic apparatus provided from an external source.